At present, LED is widely used in different lighting fields as an important lighting device. Wth the increasing requirements for light color accuracy and light quality (such as stroboscopic), the dimming characteristics of LEDs have become a basic requirement for LED lighting products.
Faced with these demands, the current industry mainly adopts PWM (Pulse Width Modulation) dimming (frequency modulation method). The advantage of this dimming method is that the color control is relatively accurate, the color algorithm is relatively simple, and the disadvantage is that it is in low brightness or the duty ratio of a light supply is very small and is prone to stroboscopic phenomena.
At present, the practice of intelligent dimming usually adopts wireless transmission and reception; The received signal is processed by MCU and output PWM control signal to the dimmer end of LED drive IC, so that the current output from the driver IC to the LED is also the PWM current, since the PWM signal is the duty cycle signal, which causes the LED to easily strobe, the smaller the duty cycle, the more severe the strobe of the LED lamp.
Most of the current front and back phase-shift dimming LED power supplies in the existing market are constant current output, which can be adjusted by directly connecting LED lights. The lamp line is simple and lighting circuit and the cost is low, which is only for one lamp. If the large area is multi-lighting, a lot of LED power supply should be used to match the lamps. In this way, the overall cost is not low. The main problem is that it is difficult to purchase LED lamps and the penetration rate is low, the installation personnel must have certain professional knowledge.
Another type of front-back phase-shifting dimming LED power supply is PWM constant voltage output, It can be adjusted according to the duty ratio of PWM, but this dimming mode LED lamp is high-frequency flashing (between 100 Hz and 10 kHz). If the PWM frequency is low, the flashing of the light is easily captured by the mobile phone. A higher frequency LED power supply will also be captured by the mobile phone, but the effect is smaller and the effect is slightly better. Such LED flashing will affect the human eye, which is not good for vision. Striping interference will appear in the image when taking pictures or recording with a mobile phone, which is not an ideal lighting fixture.